The Dynamics of Aristotelian Natural Philosophy from Antiquity to the Seventeenth Century (MEDIEVAL AND EARLY MODERN SCIENCE) 9004122400, 9789004122406

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The Dynamics of Aristotelian Natural Philosophy from Antiquity to the Seventeenth Century (MEDIEVAL AND EARLY MODERN SCIENCE)
 9004122400, 9789004122406

Table of contents :
Title Page
Copyright Page
Table of Contents
The Tradition of Aristotelian Natural Philosophy. Two Theses and Seventeen Answers
Modifications of the Method of Inquiry in Aristotle's Physics l.1: An Essay on the Dynamics of the Ancient Commentary Tradition
Latitude of Forms in Ancient Philosophy
The Sweetness of Honey: Philoponus against the Doctors on Supervening Qualities
Status and Method of Psychology according to the Late Neoplatonists and their Influence during the Sixteenth Century
The Aristotelian Foundations of Arabic Mechanics: From the Ninth to the Twelfth Century
Medieval Natural Philosophy: Empiricism without Observation
Matter and Form in Thirteenth-Century Discussions of lnfinity and Continuity
The Notion of Dimensiones indeterminatae in the Commentary Tradition of the Physics in the Thirteenth and in the Early Fourteenth Century
John the Canon on Time and Motion. A Case Study in Aristotelian Natural Philosophy and Early Scotism
Space and Spirit in the Transition from Aristotelian to Newtonian Science
Aristotle and Galen on Neutral Bodies. Perspectives on Aristotle's and Galen's Auctoritates in Late Medieval and Renaissance Medicine
Italian Aristotelians on the Debate over the Subalternation of Medicine to Natural Philosophy
University Natural Philosophy in Renaissance Italy: The Decline of Aristotelianism?
The Social Situation of the Study of Aristotelian Natural Philosophy in the Sixteenth and Early Seventeenth Centuries
Natural Science and Human Knowledge in Giordano Bruno's Comments on Aristotelian Physics
The Erosion of Aristotelianism. Confessional Physics in Early Modern Germany and the Dutch Republic
The Aristotelianism at the Core of Leibniz's Philosophy
Index of Names
List of Contributors

Citation preview



JOHANNES M.M.H. THIJSSEN University ofNijmegen

CHRISTOPH LUTHY University ofNijmegen

Editorial Consultants joEL BIARD, University of Tours University of Helsinki joHN E. MURDOCH, Harvard University ]UR.GEN RENN, Max-Planck-Institute for the History of Science THEO VERBEEK, University of Utrecht SIMO KNmrrTILA,






This book is printed on acid-free paper.

Die Deutsche Bibliothek - CIP-Einheitsaufnalune The dynamics of Aristotelian natural philosophy from Antiquity to the seventeenth century I ed. by Cees Leijenhorst, Chistoph Luthy andjohannes M.M.H. Thijssen. - Leiden ; Boston ; Koln : Brill, 2002 (Medieval and early modern science; Vol. 5) ISBN 90-04-12240-0

Library of Congress Cataloging-in-Publication Data Library of Congress Cataloging-in-Publication Data is also available

ISSN 1567-8393 ISBN 90 04 12240 0 © Copyright 2002 l!J Koninklijke Brill .NV, Leiden, The Netherlands

All rights reserved. No part ef this publication may be reproduced, translated, stored in a retrieval system, or transmitted in any farm or l!J any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission from the publisher. Authorization to photocopy items far internal or personal use is granted l!J Brill provided that the appropriate fees are paid direct[y to The Copyright Clearance Center, 222 Rosewood Drive, Suite 91 0 Danvers MA 01923, USA. Fees are sul!ject to change. PRINTED IN THE NETHERLANDS

TABLE OF CONTENTS Preface . . . . . . . . . . . . . . . . . . . . . . . . CHRISTOPH LUTHY, CEES LEIJENHORST AND JOHANNES M.M.H. THIJSSEN, The Tradition of Aristotelian Natural Philosophy. Two Theses and Seventeen Answers FRANS AJ. DE HAAS, Modifications of the Method of Inquiry in Aristotle's Physics l.1: An Essay on the Dynamics of the Ancient Commentary Tradition RICHARD SoRABJI, Latitude of Forms in Ancient Philosophy . . . . . . . . . . . . . . . . . . . SYLVIA BERRYMAN, The Sweetness of Honey: Philoponus against the Doctors on Supervening Qualities . PETER LAUTNER, Status and Method of Psychology according to the Late Neoplatonists and their Influence during the Sixteenth Century . . . . MOHAMMED ABATTOUY, The Aristotelian Foundations of Arabic Mechanics: From the Ninth to the Twelfth Century . . . . . . . . . . . . . . . . . . . . . . . EDWARD GRANT, Medieval Natural Philosophy: Empiricism without Observation. . . . . . . . . . . . . . . . . . CECILIA TRIFOGLI, Matter and Form in Thirteenth-Century Discussions oflnfinity and Continuity . . . . . . . . SILVIA DONATI, The Notion of Dimensiones indeterminatae in the Commentary Tradition of the Physics in the Thirteenth and in the Early Fourteenth Century DIRK-JAN DEKKER,John the Canon on Time and Motion. A Case Study in Aristotelian Natural Philosophy and Early Scotism . . . . . . . . . . . . . . . . . . EDITH SYLLA, Space and Spirit in the Transition from Aristotelian to Newtonian Science . . . . . . . . TIMO JouTSIVUO, Aristotle and Galen on Neutral Bodies. Perspectives on Aristotle's and Galen's Auctoritates in Late Medieval and Renaissance Medicine . . . . . . HEIKKI MIKKELI, Italian Aristotelians on the Debate over the Subalternation of Medicine to Natural Philosophy . DAVID A. LINES, University Natural Philosophy in Renaissance Italy: The Decline of Aristotelianism? . . .




57 65 81 109 141 169 189 2 25 249 289 307 325



CHARLES LOHR, The Social Situation of the Study of Aristotelian Natural Philosophy in the Sixteenth and Early Seventeenth Centuries. . . . . . . . . . . . . LEEN SPRUIT, Natural Science and Human Knowledge in Giordano Bruno's Comments on Aristotelian Physics CEES LEIJENHORST & CHRISTOPH LUTHY, The Erosion of Aristotelianism. Confessional Physics in Early Modern Germany and the Dutch Republic . . . . . . . . . CHRISTIA MERCER, The Aristotelianism at the Core of Leibniz's Philosophy . . . . . . . . . . . . . . . Bibliography . . . Index of Names . . List of Contributors

343 349

375 413 441



PREFACE This book is the strongly modified result of a four-day conference held in August 1999 in the Dutch resort of Berg-en-Dal close to the city ofNijmegen. Under the title "The Dynamics of Natural Philosophy in the Aristotelian Tradition (and beyond): Doctrinal and Institutional Perspectives," this conference brought together scholars in the history of philosophy and of science who are in some way or another engaged in understanding the history of Aristotelian natural philosophy. As the organisers, we took great pains to invite members of scholarly groups who would, for reasons of disciplinary boundaries, not easily have otherwise met. We were particularly keen on uniting scholars working on the Greek commentators on Aristotle with those working on the Arabic tradition and on the Aristotelian traditions of the Latin Middle Ages, the Renaissance, and the seventeenth century. Our second concern was to bring to one table scholars for whom Aristotle and the Aristotelian commentary tradition are of philosophical or doctrinal interest, and those for whom Aristotelian natural philosophy represents primarily a scientific, or proto-scientific, endeavour. The reasons behind our belief in the necessity of such a widely defined intellectual encounter were sent out to guests in a statement of purpose, the essence of which is explained in the Introduction to this book. Although our statement did not meet with universal approval, it had the desired effect of guaranteeing that the debates of the Berg-en-Dal Conference were engaging and to the point. The present book will, we hope, convey some of the spirit of that conference. It should be mentioned that although they are not here represented with a chapter of their own, the following scholars have contributed to the conference either with a paper, as panel leaders, or in discussion and thus have in various ways contributed to the shape and contents of what you now hold in your hands: Jan Aertsen, Paul Bakker, Constance Blackwell, Paul Richard Blum, Henk Braakhuis, Jozef Brams, Stefano Caroti, Dennis Des Chene, Griet Galle, Helen Hattab, Marcus Hellyer, Maarten Hoenen, Machiel Karskens, Eckhard Kessler, Onno Kneepkens, Simo Knuuttila, Pieter De Leemans, Ian Maclean, Charlotte Methuen, John Murdoch, William Newman, Carla Rita Palmerino, Olaf Pluta, Lambertus de Rijk, Sophie Roux, Andreas Speer, Carlos Steel, Paul Tummers and Theo Verbeek. This is the place to thank all those who have contributed either to the conference or to the book that has resulted from it. First of



all, we should like to express our great gratitude to the European Science Foundation for sponsoring this conference in the context of the network "Early Modern Thought: Reconsidering the Borderline Between the Middle Ages and Early Modern Times." Through its generous research grant (no. 200-22-295), the Netherlands Organisation for Scientific Research (Nwo) allowed the Centre for Medieval and Renaissance Natural Philosophy at Nijmegen to act as the Conference's second sponsor. We should also like to thank Frans de Haas, who as a member of the steering committee organised those parts of the conference that dealt with the Greek commentary tradition, and Marlies Veerkamp, who assisted with many of the administrative and book-keeping aspects. The production of this book would not have been possible without the help ofJulian Deahl, Marcella Mulder and Gera van Bedaf of Brill Academic Publishers and of their staff. Paul Scholey has carefully edited and proofread some of the chapters. With great diligence and patience, Corien Bary has prepared the manuscripts for print and has established the bibliography and the index. The book's layout and high-quality typography are, like those of all other volumes in the Brill series Medieval and Early Modern Science, due to the skilful work of the Typographica Academica Traiectina and in particular to Johannes Rustenburg's unending patience. The Editors


I .



Two Theses: Against Essentialism and against Epochalization

This book is the fruit of the conviction that we need a fresh approach to the history of Aristotelian natural philosophy from its origins to I 700 and beyond. This conviction is rooted in the following two theses, to which the chapters of this book directly or indirectly respond. The first thesis states that the term "Aristotelianism" has no clear essence. There is no single definition of "Aristotelian"; on the contrary, for every case to which it is applied, this predicate needs to be clarified. It is obviously not sufficient to write a commentary on a work by Aristotle to count as an "Aristotelian," as is documented by the Neoplatonistcommentators oflate Antiquity. The case oflate medieval natural philosophers, for most of whom Aristotle's authority was unrivalled, is only apparently more straightforward. In a context in which "natural philosophy" was nothing above and beyond the study and explanation of Aristotle's libri natura/,es, it is tautologous to speak of "Aristotelian natural philosophy." But for the philosophers concerned, the issue was not whether Aristotle was right, but whether Averroes, Albert the Great, Thomas Aquinas, Duns Scotus, William of Ockham, John Buridan, or some other interpreter had understood him correctly. The strong school formation produced competing "Aristotelianisms," in each of which extraneous religious and Platonist ingredients were forcefully present. The proliferation of rivalling interpretations became even more accentuated in the fifteenth and sixteenth centuries as the result of the rediscovery of the Greek commentators and the introduction of new analytical tools. The definition of "Aristotelianism" is rendered yet more complicat* Drafts of this introductory chapter have circulated up and down the corridor of the Center for Medieval and Renaissance Natural Philosophy at the University of Nijmegen. We should like to thank Paul Bakker, Frans de Haas, Maarten Hoenen, Carla Rita Palmerino, and Olaf Pluta for their incisive comments.





ed by the phenomenon of certain self-declared seventeenth-century "anti-Aristotelians" whose doctrines look (in presentation and terminology) distinctly more "Aristotelian" than those of some of their contemporaries who, for reasons of sincere conviction or fear of censorship, posed as "Aristotelians." These cases take us further to the issue of whether "Aristotelian" is an actor's category or instead the historian's. For only a small fraction of those whom historians identify as "Aristotelians" would have found this label meaningful. Many might have answered that Aristotle was their main textual authority in certain fields, but not in others-Aristoteles optimus naturalis, sed pessimus metaphysicus, for example-,and that, at any rate, his views needed everywhere to be adjusted to religious truths. Others might have accepted the label, believing to be faithful members of the secta Peripateticorum, but without recognizing just how much extraneous Platonism and Neoplatonism they had absorbed by reading Aristotle through the eyes, for example, of Avicenna. In short, then, we shall always meet with counter-examples that document that a definition of "Aristotelianism," either as a specific worldview, or as a set of core convictions, or as a practice (commenting or teaching), or again as a conscious philosophical affiliation ("Aristotelicus sum") is falsifiable. The second thesis states that for the writing of the history of natural philosophy, the traditional division into epochs is not only useless but misleading. Particularly in the case of the Latin world between 1200 and I 700, the trisection into Middle Ages, Renaissance and the early modern period makes little sense for someone who is interested in the teaching of philosophia naturalis at the universities. In that entire period, we find no unequivocal moment of rupture. However popular Plato may have been among humanists and at the courts in the fifteenth and sixteenth centuries, he did not replace Aristotle in the philosophy curricula. Nor was 1600 the turning-point as which it is often depicted. However strongly the basis of Aristotelian cosmology and matter theory were being challenged in the period between Copernicus' De revolutionibus (1543) and Isaac Newton's Principia ( 1687), the teaching of natural philosophy remained astonishingly unaffected until late in the seventeenth century and in many parts of Europe and in the colonies until much later. It seems to us that we may claim even more: Natural philosophy as a discipline did not survive the emergence of the specialized sciences. And where it survived at all, it continued to evolve in the Aristotelian tradition. Although this book represents maybe the first attempt to analyze, for the entire period of time that leads from the first Greek commentators to the end of the seventeenth century, what it meant



to do "Aristotelian natural philosophy," the two theses themselves are not new. They have been anticipated or implied by other authors. Over the past decades, it has become clear that the depiction of Aristotelianism as a monolithic, immobile, and intellectually sterile worldview originated in the early modern period with philosophers such as Thomas Hobbes, who accused scholastic Aristotelians of engaging in meaningless prattle: There is yet another fault in the discourses of some men which may also be numbered amongst the sorts of madness, namely, that abuse of words, whereof I have spoken before .... And that is, when men speak such words as, put together, have in them no signification at all, but are fallen upon by some through misunderstanding of the words they have received and repeat by rote; by others from intention to deceive by obscurity. And this is incident to none but those that converse in questions of matters incomprehensible, as the Schoolmen, or in questions of abstruse Philosophy. 1 Even more effective than such fiery invectives was that extraordinary moment of discontinuity that Descartes managed to create. Of all the novatores, he was the first who succeeded, at least in the eyes of his contemporaries, in replacing the Aristotelian system with an equally complete alternative. If for two hundred and fifty years now, Descartes has been acclaimed as the "Father of modern philosophy," this honorific title is the result not only of his epistemological method of radical doubt and his attempt to deduce all of metaphysics and physics from indubitable first principles, but also of his total unwillingness to refer to previous authors or texts. This apparent textual discontinuity created an unprecedented tabula rasa situation. Indeed, one can read Descartes' work without needing to know anything about the philosophical context in which it was written. 2 To philosophically equipped contemporaries, it was evident that much of Descartes' philosophy responded to and borrowed from the dominant philosophy of the schools. Some perceived in fact such a resemblance that they even tried to devise a unified "Aristotelico-Cartesian" doctrine. 3 But whatever continuities in vocabulary and doctrine there existed between the philosophy of the schools and that of Descartes, these were no longer recognizable to North European readers from

1 Hobbes, Leviathan [Curley], part I, ch. 8, p. 46. A recent assessment of Hobbes' attitude towards Aristotle is found in Sorell, "Hobbes and Aristotle." 2 How Descartes became the "Father of modem philosophy" is told by Schutt, Die Adoption. 3 See, for example, de Raey, Clavis philosophiae universalis.




the eighteenth century onward. For them, "Cartesianism" came to designate the beginning of modernity and "Aristotelianism" the defeated medieval paradigm. This meant that a rich world to which figures as different as Philoponus, Avicenna, William of Ockham, or Pietro Pomponazzi had contributed, now contracted into a single "-ism." Even more unfairly, "Aristotelianism" in its entirety came to be equated with "scholasticism," a word used disparagingly to mean a slavish attitude towards Aristotle's authority, a bookish approach to truth, a syllogizing method of investigation that was both circular and sterile, and ridiculous concerns with quodlibetal questions regarding the number of angels that could dance on the head of a pin. 4 These stereotypical views all capture some of the numerous facets of the long Aristotelian tradition in natural philosophy, but none of them can be generalized into a definition of "Aristotelianism," because for each of them, the counter-evidence outweighs the evidence. However, to launch an anti-essentialist reading of Aristotelian natural philosophy does not imply that the de-essentialized terms themselves are meaningless or need to be abolished. Quite evidently, no other ancient author left such a rich array of mutually interlocking treatises to posterity as Aristotle. Of the seventy works by Democritus listed by Diogenes Laertius, for example, all are lost. It is also hard to imagine that there might have existed an even more comprehensive and detailed model of the natural world than that developed in Aristotle's libri naturales, which explains the behavior of stars and stones, souls and plants, elements and animals, together with the principles underlying their generation and the mental processes that permit us to understand all of these phenomena. It is therefore instinctively comprehensible why the Lyceum, the school founded by Aristotle, should have continued to use his libri naturales for teaching and as a starting point for further investigations. In this sense, to speak of the tradition of Aristotelian natural philosophy must mean, first of all, to speak of a tradition of thinking about natural phenomena with reference to, or in the terminology of, doctrines expounded in Aristotle's libri naturales. As obvious as this clarification must at first appear, the point is that in spite of their shared literary reference point, Aristotelian natural philosophers diverged from one another in the most remarkable ways.

4 On the complex evolution of the term "scholastic" from its coinage in the Middle Ages until the eighteenth century, see Quinto, "Scholastica."



The observed variety between these philosophers, and the doctrinal elasticity displayed in the two thousand-year tradition of Peripatetic philosophizing in fact prompts two questions, both of which are addressed in this book. The first asks whether there are definable conceptual limits beyond which one cannot go without leaving the Aristotelian precinct. The second asks about the factors-conceptual, educational, social, political, and religious-that were responsible for the observed developments within the Aristotelian tradition of natural philosophy. To the first question, concerning the conceptual limits, contrasting answers have been given in the scholarly literature. 5 The bone of contention is whether "Aristotelian" is a term that applies to members between which there exists merely a "family resemblance," or whether, by contrast, "Aristotelianism" possesses either a systematic structure or a doctrinal hard core that cannot possibly be abandoned without eo ipso leaving the Aristotelian paradigm. 6 Both approaches have their strengths and their weaknesses, the problem lying chiefly in the fact that during certain historical periods, the practice of commenting on Aristotle's libri naturales was more open-ended, flexible and, as it were, quodlibetal, whereas in others, emphasis lay on demonstrating its systematic and closed character. Charles Schmitt is doubtlessly right in insisting that in the fifteenth and sixteenth centuries, Aristotelianism was defined "not so much by a common system of ideas as by common source materials, a common terminology, a common set of definitions, and a common method of discussing these problems." 7 But when we look at late sixteenth and seventeenth-century textbooks, we cannot help but feel that we are in the presence of a highly inflexible "system of ideas." 8 This impression of rigid compactness is conveyed, for example, in that well-known passage in Galileo's Dialogue of i632, in which Sagredo intuits what passes through the mind ofSimplicio, the Aristotelian, as Salviati, the Galilean, destroys his conceptual cosmos with the tools of empirical experience:

5 A number of these answers are discussed in Thijssen, "Continuity and Transformation." 6 Wittgenstein's term of "family resemblance" is applied by Schmitt, Aristotl,e and the Renaissance, pp. 111-112. An essentialist, typological approach is rehearsed, e.g., by Grant, "Ways to Interpret." 7 Schmitt, Aristotl,e and the Renaissance, p. 10. 8 The systematic rigor and homogeneity of early seventeenth-century textbooks in natural philosophy is carefully analyzed by Reif, Natural Philosophy.





Simplicio is confused and perplexed, and I seem to hear him say: Who would there be to settle our controversies, if Aristotle were to be deposed? What other author should we follow in the schools, the academies, the universities? What philosopher has written the whole of natural philosophy, so well arranged, without omitting a single conclusion? Ought we to desert that structure under which so many travellers have recuperated? Should we destroy that haven, that Prytaneum where so many scholars have taken refuge so comfortably; where, without exposing themselves to the inclemencies of the air, they can acquire a complete knowledge of the universe by merely turning a few pages? Should that fort be levelled, where one may abide in safety against all enemy assaults? 9

But importantly, this nostalgic depiction of Aristotelianism as "the whole of natural philosophy, so well arranged," reproduces not only an ironic outsider's view, because we also encounter it in the natural philosophy textbooks themselves. We possess testimonies of early modern professors of natural philosophy who describe the reasons for their unwillingness to forsake their coherent and allencompassing systemjust because some parts of it seemed to be falsified by "new experiences." As professors, they viewed Aristotelian natural philosophy not only as a worldview, but also as an educational tool the didactic rigor of which they were reluctant to abandon in favor of tidbits of empirical findings. If at all, Aristotle could only be replaced by an equally complete and deductive system. This is, it seems, what the German philosopher Johannes Combach wished to say when in 1620 he expressed the hope that one day someone will finally arise, who will show us more perfect principles, and gather into one certain system what Paracelsus and other teachers of truth have handed down here and there in scattered fashion, and deliver to us the order and connection of true physics. 10

The inflexibility of the Aristotelianism of early modern textbooks explains why the empirical sciences developed in "a spirit of revolt against the authority of Aristotle." 11 It also explains why men such as Descartes, Borelli or Newton tried to devise natural philosophical systems that could replace Aristotle's. Already at the end of the eighteenth century, however, their attempts at system building were Galilei, Dialogue [Drake], p. 57. Combach, Physicorum libri, Preface to the Reader, p. 2: " ... ut tandem monstret, et quae Paracelsus aliique veritatis magistri sparsim hinc inde tradidemnt, in unum quoddam systema colligat, veraeque physicae ordinem et connectionem no bis exhibeat." Latin quote from Reif, Natural Philosophy, p. 265. 11 Dijksterhuis, Mechanization of the World Picture, p. 264. 9




sometimes criticized for having produced prisons that were as closed and dark as Aristotle's, which they had tried to replace. Systems of natural philosophy, however modern, blocked the freedom of the hypothetically minded experimental philosopher. 12 But when it is said that Aristotelian natural philosophy was unable to modify itself, though confronted with falsifying evidence, and subsequently broke down "under its own weight," this is not only an exaggeration, but simply wrong. Introductory textbooks were not the only face of early modern Aristotelian natural philosophy. In Protestant lands, this discipline developed in various new directions, not only in response to the results of the empirical sciences, but also under the impulse of confessional reasons. In Catholic lands, particularly as a consequence of the Jesuits' educational reforms, it was granted a new life, integrating Tychonic cosmology, Galilean kinematics, Newtonian dynamics, and further scientific ingredients into its structure. 13 It is usually overlooked that a thoroughly updated Aristotle continued to appeal to those who understood themselves not just as physicists, chemists, or biologists, but more ambitiously as natural philosophers. 14 In fact, it is a salubrious antidote to the false essentialist belief in the succession of paradigms to know that even in the twentieth century, books continued to appear in which quantum mechanics, relativity theory, or Darwinism were analyzed with the tools of an Aristotelian vocabulary. 15 12 See, for example, Genovesi, Elementa physicae experimentalis, vol. I, p. 32: "Verum postquam philosophia desiit esse sub Aristotelis tyrannide, et Renati [sc. Cartesii] dictatura, cito concidit, nee Leibnitii, aut Newtoni auctoritas ad monarchiam creandam valuere, respublica philosophorum primum aristocratica, mox democratica evasit. Igitur philosophi ferme omnes, auctoritatis jugo excusso, suam rationi, et experimentis dignitatem restituerunt." 13 For attempts to integrate the principles of Galileo's physics into an essentially Aristotelian framework, see Baldini, "The Development of Jesuit 'Physics' in Italy." For the complex interplay between censorship and imposed unity, on the one hand, and doctrinal freedom, on the other, in early modern Jesuit works on physics, see Hellyer," 'As the Authority of My Superiors Commands.'" 14 On the failure of the natural sciences to replace natural philosophy, see Liithy, "What to Do with Seventeenth-Century Natural Philosophy?," esp. pp. 173-175. 15 For illustration's sake, let us mention that in the third edition of his Cosmologia of 1945, the Jesuit Petrus Hoenen begins by invoking Husserl's observation that natural scientists are not always good natural philosophers, adding that "hae voces a nonnullis scholasticis cum plausu accipiebantur" (p. iv). His work, the subdivisions of which sport traditional titles as "De quantitate, loco, spatio" (lib. 1), "De qualitatibus corporeis" (lib. n), "De continuo fluente" (lib. m), or "De ipse essentia corporis naturalis" (lib. 1v), etc., applies more than a millenium of commentators on Aristotle's works (ranging from Philoponus over Averroes and Albert the Great to Suarez) to





We have seen, then, that the question concerning the definition and conceptual limits of Aristotelian natural philosophy quickly turns into a question concerning its degree of rigidity or flexibility, respectively. And with this, we effortlessly move on to our second question, concerning the factors that were responsible for the various doctrinal developments within Aristotelian natural philosophy. The present book assembles a series of case studies that sketch such developments and provide explanations for them. The overarching question is always how it was possible that the same set of libri naturales could engender such a wide range of divergent interpretations. Besides the hermeneutic truth that for every text, there will be as many interpretations as there are readers, there existed various additional reasons that pushed commentators and interpreters to go "beyond" a mere interpretation and develop Aristotle's presumed theory further. And there are, it seems to us, at least eight ways in which a comment can "go beyond" the text it purports to comment on. But every such "going beyond" marks a point where the tree of interpretation branches into yet another set of possibilities and meanings. Let us mention these eight ways in ascending order of gravity. First of all, we must mention the problem of vocabulary. Not only was Aristotle himself an extraordinarily fertile inventor of new philosophical terms, but all of the abstracta he invented had later to be translated into Arabic, Syriac, Latin, and European vernacular languages. While Aristotle's Greek readers had to grapple with his neologisms as we grapple with Heidegger's or Derrida's private languages, translators had to find ways of translating these abstract terms, for which there existed no equivalents in their own languages. But before a terminological consensus was reached, there was always and inevitably a period in which competing translations co-existed, which in turn generated competing interpretations. This pattern can be observed with the first generations of Arab translators, the Latin translators of the late twelfth and early thirteenth centuries, and again with the humanists who tried to replace the medieval translations by others that would not have violated Cicero's linguistic sensibilities. Humanists, for example, balked at the wooden twelfthcentury term quidditas on the grounds that it was not contained in the classical Latin vocabulary, preferring instead essentia, a term invented by Seneca and Cicero to translate ouaia. Since Arabic, unlike

such contemporary issues as the interpretation of quantum mechanics, matter-energy dualism, or the Heisenberg uncertainty relation.



Latin, possesses no equivalent of the Greek verb Elvm, Arab-speaking translators had to find a different solution. They came up with the idea of adding a suffix to the interrogative pronoun "what?" ( mii). The medieval quidditas, however, is nothing else than a literal translation of the Arabic miihiyya. 16 But it is evident that there is not just a different ring to quidditas than there is to essentia, but that the two translations also imply a different interpretation of what Aristotle may have meant by ovaia. Second, foremost among the tasks commentators set themselves was that of resolving perceived tensions between different textual passages. Aristotle gives, for example, two characterizations of elements, one in terms of natural places and the other in terms of primary qualities. It is easy to see how the attempts at reconciling these two explanations could result in new theories. There are even more extraordinary examples. Although Aristotle lashes out at the atomists wherever he can, the fourth book of his Meteorology uses particles and pores to explain the behavior of specific substances. Sixteenth-century commentators wrote that in this book, "Aristoteles Democrizat" - that he had been caught in jlagrante delicto using Democritean atoms-, and they employed this as a sign that they, too, were authorized to analyze material compounds in terms of individual particles.17 Given that hylemorphism is usually understood as a "core" element of Aristotelianism and atomism as its declared enemy, this atomizing Aristotle represents an extreme example of the possibilities of interpretation. Third, commentators also felt that they had to fill in doctrines that Aristotle had either omitted or only sketched with insufficient precision. Such attempts to extend and complete his world explanation could not but result in new "Aristotelian" doctrines that had no, or only a slim, basis in Aristotle himself. Well-known cases in point are the development of an "Aristotelian" optics and chemistry, or of theories of projectile motion. A fourth type of doctrinal extension resulted from the erroneous acceptance of spurious works into the Corpus Aristotelicum. To accept 16 On the introduction of the Greek philosophical and scientific vocabulary into Arabic, see Endress, "The Language of Demonstration." 17 The phrase "Aristoteles Democrizat" occurs in Pomponazzi, Dubitationes, dub. 92, fols. 43 v-44r, and similarly in dub. I 02, fol. 4 7v, where Pomponazzi writes: "Videtur ibidem Aristoteles Democrizare, nam incidit in quaestionem Democriti. Qui voluit quod actio fiat per poros." On the influence of Meteorology rv on sixteenthcentury theories of mixtures, see Luthy, "An Aristotelian Watchdog." See also Newman, "Corpuscular Alchemy."





the authenticity of, say, the Liber de causis, the De mundo or the Quaestiones mechanicae (the last two being still accepted by some scholars as genuine) meant to understand Aristotle in the light of a number of doctrines that were (probably) not his own. In the Arab Middle Ages, for example, acquaintance with the Quaestiones mechanicae led to the development of an Aristotelian tradition in mechanics. 18 Fifth, the interpretation of Aristotle's natural philosophy was forcefully influenced by the assumption on the part of many commentators that Aristotle's natural philosophy was the result of a deductive method, or that it represented a closed system erected on the foundations of first principles. The temptation to make all of Aristotle's physical or biological views concord with the presumed scientific method expounded in Posterior Analytics or alternatively to derive them from first principles found in the Metaphysics was strong. Extraordinary examples of the power of this temptation are found in those late sixteenth-century foldable tables of Ramist inspiration, on which the most remote theme ever touched upon by Aristotle is represented as a tiny twig that through a great many dichotomous biforcations is somehow linked to the mighty trunk of philosophy, the roots of which are formed by metaphysical principles. The sixth type of doctrinal extension was brought about by attempts to reconcile Aristotle's views with that of other authorities. Such attempts were, for example, the result of the conviction that, being Plato's student, Aristotle must have been a Platonist. Such views were widespread in late Antiquity and emerged again at the end of the fifteenth century. Another example is the assumption, widespread in the thirteenth and fourteenth centuries, that Aristotle could only serve as the basis of natural philosophical teaching at European universities if he was first brought into agreement with scriptural-or revealed-truth. 19 It was of course not presumed that Aristotle had been a pro to-Christian, but rather that either his science agreed better with Christianity than that of any other philosopher, in that he had only been wrong in those few points where revelation would have been necessary to recognize the truth, or else that his philosophy, if carried to its true conclusions, in fact yielded the same truths as those given in revelation. But as mentioned earlier, even the wide acceptance of Aristotle as optimus naturalis and as the See Mohammed Abattouy's chapter in the present book. There are exeptions to this patern: Albert the Great and some of his followers (e.g., Siger of Brabant or Boe ti us of Dacia), for example, insisted on a separation between theology and natural philosophy. 18 19



pagan philosopher most compatible with sacred truths did not prevent a fragmentation into rivalling schools, which accused each other of heretically perverting Aristotle's true intention by following the wrong teacher (in the case of the Thomists and Albertists) or the wrong methodology (in the case of the Scotists and nominalists). 20 A seventh type of doctrinal extension was brought about by attempts to make Aristotelian natural philosophy agree with the chief scientific authorities of Antiquity, notably in the empirical or mathematical sciences. The most obvious cases are that of Ptolemaic astronomy and Galenic medicine: It was tried to adjust Aristotle, Ptolemy, and Galen in such a way that they could form a doctrinal continuum, in which Aristotle could play the role of the provider of the principles on which the subordinated empirical sciences could be erected. One must also mention the attempt, already made in the days of the Greek commentors, of bringing Aristotle into agreement with Euclid by axiomatizing his doctrines. The eighth and last type of doctrinal development is found in commentaries whose main purpose is no longer that of explaining, applying, or systematizing Aristotle's philosophy, but instead that of presenting the commentator's own philosophy. We find cases of such commentaries from the earliest time until the seventeenth century. Already Aristotle's second successor as head of the Lyceum, Straton ofLampsacus, commented on the hylemorphism of his predecessor in the light ofDemocritean materialism. In the seventeenth century, we have the prominent case of Descartes, who at one time contemplated the idea of presenting his philosophy in the form of a counter-cursus appended to a reprinting of the Summa quadripartita of the Scotist philosopher Eustache of Saint Paul. In other words, a philosopher's decision to write a commentary on Aristotle or to follow the literary format of Aristotelian commentaries or textbooks does by itself not say anything about the author's doctrinal agreement with the Philosopher. 21 The eight ways of "going beyond" Aristotle just mentioned have all spoken of commentators as if they had been unfettered intellectuals. The dynamics of the Aristotelian tradition in natural philosophy can, however, not be appreciated if external factors are omitted. Who


2 For a comprehensive analysis of school formation in the later Middle Ages, see Hoenen, "The Medieval Via Moderna. " 21 On the philosophical independence of the Greek commentators, see Sorabji (ed.), AristotlR Transformed. Cf. also Sharples, "Introduction: Whose Aristotle?" On Descartes and Eustache of Saint Paul, see Ariew, Descartes and the Last Scholastics.





wrote commentaries or taught Aristotelian natural philosophy? Who constituted the audience? In which context, with what incentives and under what constraints did natural philosophers act? Were there rivaling philosophical schools to combat, local bishops to please, university students to be educated towards higher degrees in medicine or theology, competing religious orders to be outwitted, or confessional foes to be confuted? The institutional, religious and social embedding of the commentators explains much about the nature of their enterprise. Whether a commentator worked in a polytheistic, Muslim or Christian environment was of course particularly pertinent ifhe belonged to a priestly class or used Aristotle to explain the cosmos qua divine creation. Particularly for the late medieval situation, it has been claimed that natural philosophy was about nature only insofar as nature was God's creation, and that the "God-oriented" nature of this discipline strongly limited both its Aristotelian and its scientific character. 22 Of equal importance is also the use to which Aristotelian commentaries or textbooks were put. It has often been argued that in North Italian universities, natural philosophy was propaedeutic visa-vis medicine, which would explain, for example, the presence of new empirical and scientific material found in the sixteenth-century works of Paduan philosophers; whereas in Parisian-type universities, natural philosophy was studied by future theology students, which would explain the greater emphasis on the link between metaphysics and physics. Over the past decades, the Aristotelian tradition has become contextualized and historicized in the various ways that have just been mentioned. As far as the Greek commentary tradition is concerned, its diversity and richness is emerging with ever increasing clarity, as the translations of the group assembled by Richard Sorabji see the light of the day. The forthcoming publication of a three-volume synthesis entitled The Philosophy of the Commentators, 200-600 AD, also edited by Sorabji, promises to allow historians of philosophy for the first time to understand the complex evolution of the Greek commentary tradition as a whole. 23 22 See especially the recent debate over the dependence or independence, respectively, of natural philosophy vis-a-vis theology between Andrew Cunningham and Edward Grant, which started with Cunningham, "How the Principia got its Name," and French e.a., Before Science, and continued with Grant, "God, Science, and Natural Philosophy"; Cunningham, "The Identity of Natural Philosophy"; Grant, "God and Natural Philosophy"; and Cunningham, "A Last Word." 23 This work is scheduled to be published in 2003 by Duckworth.



By contrast, the impact of the Greek commentators on the Renaissance is neither sufficiently appreciated nor completely understood. However, a very important start has been made with Charles Lohr's carefully annotated compilations of Renaissance Latin Commentaries, which shed much light on the impact of the rediscovered Greek texts, particularly on Italian Aristotelians. The facsimile reprints in the ongoing series Commentaria in Aristotelem graeca, versiones latinae temporis resuscitatarum litterarum, also edited by Lohr, furthermore render some important Latin translations of Greek commentaries more accessible. As for medieval Aristotelianism, its vitality and diversity has been recognized ever since the publication of the important studies by Pierre Duhem and Anneliese Maier, which managed to establish very high scholarly standards for medievalists. However, the evident tension between Duhem's apologetic view of medieval philosophy as the direct forerunner of modern science and Anneliese Maier's more sceptical and discontinuist view have until today continued to play a role in the historiographical debates in the history of science. Furthermore, as more texts become accessible, it also becomes evident to what extent the method of counterfactual thinking ex potentia Dei (which some scholars, but not others, attribute to the impact of the condemnation of 1277) allowed for speculative and innovative ideas in the fields of cosmology and psychology, which had an afterlife well into the early modern and modern centuries. 24 In other areas of the history of philosophy, the appreciation of the Aristotelian tradition came about more slowly. In 1954, when Paul Oskar Kris teller presented the Martin Classical Lectures at Oberlin College, he still had to combat the view that "the Renaissance was basically an age of Plato, whereas the Middle Ages had been an age of Aristotle." Kristeller insisted that the "Aristotelian tradition, though exposed to attacks and subject to transformations, continued strongly and vigorously to the end of the sixteenth century and even later." 25 Thirty or so years later, when Charles Schmitt gave the Martin Lectures, he corrected a few other misconceptions about Renaissance Aristotelianism. In particular, he demonstrated that the Aristotelian tradition was not the monolithic entity that it was commonly assumed to be, but was instead characterized by a range of "diverse assumptions, attitudes, approaches to knowledge, reliance on authority, uti-

24 25

See, for example, Grant, Much Ado About Nothing and Planets, Stars and Orbs. Kristeller, Renaissance Thought, pp. 24, 33-34.




lization of sources, and methods of analysis. "26 Schmitt's reassessment of Renaissance Aristotelianism has over the past decade also begun to influence the historiography of early modern philosophy. The proof that Renaissance Aristotelianism was neither homogeneous nor fossilized, but encompassed a series of evolving doctrines and schools of thought, has given life to the idea that the apparent philosophical giants of modernity existed within an intellectual world from which they not only learned their craft and later emancipated themselves, but in which they had interlocutors. Over the last years, it has become possible to liberate not just Leibniz, but also Descartes and Hobbes, from their previous isolation and insert them back into their historical surroundings. 27 The result of such an historical re-embedding cannot and should not be either a demonstration that Aristotelianism was responsible for modern science or that the novatores were less innovative than they claimed. Rather, by analyzing the Aristotelian university education of the seventeenth century's gentlemen philosophers and the system they were writing against, we appreciate their accomplishments in a different light. If Descartes spent several years on the attempt to develop a mechanistic physiology, the main reason, as has recently been shown, must be sought in his desire to replace the psychology of the schools. Since the treatment of the vegetative, sentient and rational souls constituted the capping stone of natural philosophy, Descartes felt quite rightly that his mechanistic replacement of hylemorphism would remain incomplete unless he managed to substitute the doctrines of De anima in a convincing manner. 28 What is still missing, by contrast, is an understanding of the life of Aristotelian natural philosophy, and quite generally of natural philosophy as a theoretical (rather than experimental) discipline, beyond Schmitt, Aristotle in the Renaissance, p. io. For Descartes, see above all Des Chene, whose Physiologia is an outstanding example of how to read Descartes historically, that is to say, with the mind-set of a philosophically trained contemporary. Gilson's Index scolastico-cartesien of 1913 constitutes an important precedent in this enterprise. For Hobbes, see Leijenhorst, The Mechanisation of Aristotelianism. For the most recent study of Leibniz' debts to the Aristotelian tradition, see Mercer, Leibniz's Physics. Other examples of this new historical awareness can be found in Blackwell e.a. (eds.), Philosophy in the Sixteenth and Seventeenth Centuries; in Garber e.a. (eds.), Cambridge History ofSeventeenth-Century Philosophy, where detailed attention is given to the Aristotelian setting of the main issues of seventeenth-century philosophy; and in Schobinger (ed.), Grundriss, whose eight volumes cover also those parts of Europe (Spain, Portugal, Italy, Bohemia, etc.) where Aristotle's libri naturales remained the main references for natural philosophers. 28 This is convincingly argued by Des Chene, Spirits & Clocks. 26




1650. The eighteenth, nineteenth and, as we have already mentioned, even the twentieth century produced university textbooks that offered an outline of the principles of natural philosophy and delineated the link between its principles and the data of experimental physics. Many of these books contain a historical sketch of the discipline, which are usually either fervently anti-Aristotelian or strongly pro-Aristotelian ("Aristotelian" being, typically enough, always identified with the Middle Ages), and they describe the Middle Ages either as a terrible time of intellectual tyranny or as a golden age of conceptual unity. It is, however, noteworthy that the rhetorical posturing quite often hides a basic agreement on the presentation of the subject-matter and even on terminology, although it is undeniable that a good percentage of the pro-Aristotelian works are reactionary works written by authors that were philosophically and scientifically incompetent. 29 But unfortunately, today's historians of science deal with the experimental sciences and historians of philosophy with philosophy as understood today. This division of labor confines the old discipline of philosophia naturalis to the orphanage of history. 2. Seventeen Views of Aristotelian Natural Philosophy

The seventeen chapters in this book all respond, in one way or another, to the two theses mentioned at the outset of this introduction, viz., that today's state of scholarship does no longer allow us to think of Aristotelianism as one single philosophical unit and as a school whose development was defined, or may be characterized, by using 29 The more traditionalist Catholic countries saw the publication of a lot of pseudomedieval Aristotelico-Thomist syntheses. Take as a typical case the Jesuit philosopher Garcia de Vera, whose Cursus philowphicus of i 759 followed the Jesuits' prescribed teaching method for the Province of Aragon and who begins his physics course as follows (p. 3): "Aristotelica philosophia longo saeculorum tractu scholarum theatra, mentesque sapientum tranquilla pace possedit: quousque novatores aliqui earn deturbare conati sunt, non quidem novas aperiendo sapientae vias, sed eas exarando, quas Epicurus, aliique veteres sectabantur, et quae nullo tritae sapientum vestigio oblivionis pulvere sepultae, et impervie existebant. Operae tamen pretium duxi haec systemata vobis exponere, nee enim hodierna die philosophus aestimatur, qui hanc philosophiam ignoraverit." However, the "philosopher" that emerged from Garcia de Vera's physics course was able to speak syncategorematically about infinity and knew the scriptural reasons for which it was necessary to deny the void, but he would have been intellectually cut off from the European Ripublique des lettres and ignorant of contemporary physics and philosophy.




the traditional epochal divisions. To make the contents of the individual contributions more accessible to the reader, let us single out a few pertinent points from all of them. In the first chapter, Frans de Haas investigates the very starting point of Aristotelian physics, namely Book I. I of the Physics, which defines scientific understanding as the understanding of principles, causes and elements and sketches the way in which one arrives at them. The Greek commentators initiated a discussion concerning the meaning of these twenty-two lines of text-a discussion that has still not died down and has over the centuries produced an enormous range of interpretations. However, from very early on, there existed a marked consensus to the effect that in Physics I. I, Aristotle tried to come to terms with the question of how to constitute a correct physical proof, and more specifically, with whether it is scientifically legitimate to reason from effects to causes. Moreover, Aristotle is believed to have given an answer, albeit an enigmatic one, to the question concerning the relation between method and order: Should physics proceed from general principles to specific conclusions or vice versa? Finally, Physics I. I is also generally understood to discuss the status of universal concepts and the way we acquire these. But de Haas breaks with this standard interpretation of Physics I. I, arguing that this chapter has an important, but more limited function than has been assumed. A close look at the vocabulary shows that Aristotle was arguing against Plato and his students that the study of nature can be scientific in the sense of yielding knowledge of principles. He did not speak about universals, but instead tried to explain that every inquiry proceeds from an unanalyzed whole to its analyzable primary constituents. Indeed, to introduce a work by defining the difference of his own position vis-a-vis his predecessors is typical of Aristotle's dialectical style. But why, then, should dozens of generations have misread Physics I. I? De Haas' answer is that at a very early stage in the process of interpretation, this chapter was misunderstood. Our own interpretation is in fact determined by the Neoplatonic commentators and notably by Themistius. Like all commentators, Themistius labored under specific constraints which the philosophical environment imposed on him. His reinterpretation of Physics I. I was the result of his attempt to answer the challenge presented by Alexander Aphrodisias. For instance, the issue of universal concepts emerged because of Alexander's discussions concerning Aristotle's allegedly contradictory utterances with respect to the priority of the universal (xaW oA.ou). Given that Alexander had identified universals with "common items" (xmvci), Themistius, who had a



rhetorical background, imported the rhetorical order of exposition into his reading of Physics 1.1, which he now interpreted as arguing that natural philosophy, too, should proceed from what is more general to what is more specific. This reading of Aristotle was to have an immense impact, not least in the context of the Renaissance debate concerning the relation between the order of exposition and the order of nature. By recognizing Physics 1.1 as Aristotle's reply to Plato, and Themistius' interpretation as an answer to Alexander Aphrodisias, de Haas shows how the failure to appreciate the historical connotations of technical vocabulary can lead to misinterpretations that are never, or only belatedly, recognized. The chapter by Richard Sorabji occupies itself with the "latitude of forms," another issue that troubled generations of Aristotelian commentators. The basic idea is that a given property can have various degrees. It has been commonly assumed that the discussion of latitude in Antiquity originated with Galen and his followers and flourished particularly during the Middle Ages. However, on the basis of recent research, Sorabji proves that the concept of latitude, though not the term itself ( nA.ato~), is already found much earlier, in fact already in Plato and Aristotle, where it played a role in the fields of physics, logic, metaphysics, ethics, psychology and biology. Sylvia Berryman, too, analyzes a number of philosophical contributions made by ancient commentators. Berryman studies an important question, which is related to the Aristotelian theory of mixture: How are we to explain the relationship between the qualities of the ingredients that go into the making of a substance and the properties that characterize the substance, though they are not found in its ingredients? The main protagonist of this chapter is John Philoponus, whose views on mixture strongly influenced Renaissance discussions, especially at Padua. Berryman shows how in his own analysis of the problem, Philoponus modifies the views developed by Aristotle against the atomists. Like de Haas, Berryman, too, refers to the intellectual environment in her explanation for why Philoponus should have desired to modify the Aristotelian doctrine. For Philoponus' target are physicians steeped in the Galenic tradition who describe qualities, including psychological states, as products of material mixtures. Though Philoponus does not wish to deny that qualities can be determined by the proportions of the ingredients of a mixture, he insists that many properties are not adequately explained thus. Qualities supervene on the ingredients rather than being their direct products, Philoponus argues, and he documents the truth of this view by pointing to cases where different kinds of qualities that supervene




simultaneously on a mixture may vary independently from another: Heating honey changes its color, but not its sweetness. As Berryman shows, Philoponus had to employ specific metaphysical assumptions so as to counter a reductionist account of psychological states, colors, and other supervening qualities. Peter Lautner focuses on the problematic status of the study of the soul. Given that the De anima belongs to the libri naturales, it appears that Aristotle included the study of the soul in the study of nature. Lautner explains why the Neoplatonist commentators found this inclusion contradictory. Here, in fact, we encounter a typical case in which an apparent contradiction propelled Aristotelian natural philosophy in new directions. On the one hand, Aristotle defines physics as the study of things that are both "inseparable" and "changing"; but, on the other hand, he also defines active reason as "changeless" and moreover as a "separate" part of the soul. From this it seems to follow that the study of the soul would have to constitute a separate domain of inquiry. Philoponus, for example, tried to solve this problem on the basis of his Neoplatonist metaphysical and methodological convictions, and he assigned the study of the soul to ethics and metaphysics. By contrast, the De anima commentary by Simplicius (or rather, according to Lautner, by pseudo-Simplicius) proposes that the study of the soul mediates between the study of nature and metaphysics. These views could not but influence also the way in which the proper method of doing psychology was understood. Modifying Aristotle's original doctrine, both Philoponus and Ps.-Simplicius rejected Aristotle's definition of the soul as the form of the body which has life potentially. Instead, they distinguished between various strata and faculties of the human soul. In keeping with the diachronic nature of the present book, Lautner concludes his chapter by tracing the fortuna of these Neoplatonist views in the sixteenth century. He shows that Paduan philosophers such as Marc'Antonio Genua in fact accepted Ps.-Simplicius' definition of psychology as a scientia medians. By contrast, Genua's pupil, Jacopo Zabarella, who was influenced by Philoponus, rejected Ps.-Simplicius' definition and reintroduced Aristotle's classification of psychology as the most noble part of natural philosophy. MohammedAbattouy's chapter takes us to the Arab-speaking world, which is today no longer viewed simply as the temporal storage place of Greek philosophy, but as a major contributor to the development and evolution of Aristotelian natural philosophy. Abattouy investigates the fortuna of the (pseudo?-)Aristotelian Mechanics in the hands of three representatives of the Muslim mechanical tradition from the



ninth to the twelfth century, namelyri. &s xal 6 &1'.ri~s EXEL A6yos. Translations from Philoponus' commentary on De generatione et corruptione are from John Philoponus, On Aristotle On Coming-to-Be and Perishing [Williams], slightly modified. Todd notes precedent for the expression Twv Tfi£ its object. Ps.-Simplicius does not develop this argument further, ut one may infer that the study of the soul will be the most exact scillCe ad nos. For what else could be closer to us than we ourselves? In idition, he claims that the study of the soul is worthy of veneration, nee the status of the soul transcends even that of the heavenly bod:s. In sum then, the study of the soul is even more exact than that f the of nature's most noble domain, namely, the heavenly bodies, ecause the subject-matter is both closer to us and ontologically prir. This must imply, however, that the domain of physics is ill-suited >r the study of the soul. The study of the soul is highly valuable in other respects as well. irst of all, given that the soul is capable of moving itself, it is everlast1g. 44 Furthermore, the study of the soul is akin to its subject-matter, ecause the knower and the known are very close to one anothr.45 Our awareness of our composite being is therefore clear and x.act. This is even more so in the light of the soul's capacity for ~If-reflection, since this act does not require any sense-perception, 42

The classification follows the status of the different universals, see Proclus,

primum Euclidis ElRmentorum commentarii [Friedlein], p. 49 8 ff. See also Proclus, i Platonis Timaeum commentaria [Diehl], vol. 1, p. 217 18- 22 , p. 3508- 12 , In Platonis rzrmenidem commentaria [Cousin], p. 7969-- 10 • 43 Ps.-Simplicius, Simplicii in libros Aristotelis De anima commentaria [Hayduck], p.



44 ~ros


Ps.-Simplicius uses this argument from Plato's Phaedrus, 245c in his Simplicii in Aristotelis De anima commentaria [Hayduck], p. 35 7- 1 3. Ibid., p. 711-28.



as it is governed by the intellect and not by bodily affections. However, as a consequence of the soul's temporal involvement in bodily matters, the study of the soul may be linked to physical inquiry. A good foundation for this is Aristotle's statement that the study of the soul seems to contribute a great deal to the study of nature. 46 Ps.Simplicius agrees with Aristotle, but in a way that is typical of the late Neoplatonic tradition, for he names four aspects that link the study of the soul to nature. First, sensible things cannot be known without knowledge of the sensitive faculty. 47 This implies that the study of the soul is a prerequisite for the study of nature. Secondly, sensible things are neither scientifically cognizable, nor are they realities, because only intelligible entities are fully real. As realities are studied by the intellect, knowledge of the intellect therefore contributes to knowledge of natural things insofar as these things are scientifically knowable, that is, in their having forms. Thirdly, thanks to the soul's intermediate position between intelligible and sensible entities, the study of the soul contributes to the investigation of both realms. In the case of physics, this contribution explicitly relies on a methodical principle, namely, that knowledge of effects through their causes is more perfect than knowledge that ascends by induction from effect to cause. Fourthly, the soul in not a simple meridian between the intelligible and physical domains, for physical things are somehow dependent on the soul as their principle. This is so because the soul is the principle of living beings and hence the most perfect of physical things. The soul may therefore be justifiably called the principle of all physical things. A further reason, on which Ps.-Simplicius does not elaborate here, is that the (world-) soul imposes form on matter, and is thereby the agent which brings about physical things. 48 Quite evidently, then, the two commentators have different views on the status of psychology and its contacts with other sciences. Ps.-Simplicius remains consequent in his conviction concerning the soul's intermediate position between sensible and intelligible entities by claiming that the study of the soul bears upon physics and metaphysics alike. The study of the soul not only opens the path towards an investigation of the intellect's realm, but is also the path 46 Aristotle, De anima, 4oza4-5, commented on by Ps.-Simplicius, his Simplicii in libros Aristotelis De anima commentaria [Hayduck], p. 733 ff. 47 This is an echo of Aristotle's Posterior Analytics, 641b1-4.

48 Ps.-Simplicius may have omitted this reason from the world-soul because in his commentary on the De anima, he discusses the human soul. However, he could have done otherwise, because in the tradition that followed Proclus, there was no essential difference between human soul and world-soul.



towards a better understanding of the principles underlying physical things. Philoponus has a different view of the matter. Although he accepts that the soul mediates between physical and intelligible entities, he does not found his own ideas upon this belief when discussing the link between the study of the soul and other sciences. Indeed, the sciences he surveys are not exactly the same as those discussed by his colleague in Athens. Whereas Ps.-Simplicius tries to correlate psychology to physics and metaphysics, Philoponus links psychology to physics, metaphysics and ethics. Here, then, there is little reason to speak of mediation between the various realms of being. In fact, Philoponus explicitly rejects the notion that the study of the soul can contribute to the study of nature. This may come as a surprise, since his commentary employs a vast amount of medical material to elucidate his concept of the soul. Philoponus holds that metaphysics and ethics are the sole disciplines to which psychology can be properly linked. Philoponus links metaphysics to psychology by drawing on distinctly Neoplatonic theories, whereas he links ethics to psychology by resorting to a different domain, namely, that of moral psychology as inherited from Plato, according to which the various virtues express the right attitudes of the soul, while the attitudes themselves are in harmony within the soul of the virtuous.

2.3. The Method of Psychology Methodologically speaking, the first question must concern the definition of the soul. Was Aristotle's definition sufficient? Philoponus, for one, did not think so. To show why, he drew a distinction between two kinds of activity within the rational part of the human soul (also known as the rational soul). One kind of activity is linked to the soulbody compound (this being specifically human), whereas the other kind of activity is exclusive to the rational soul. 49 When separated from the body, the soul does not engage in activities of the first type. Therefore, the essence of the soul must be separable from the body. In consequence, the proper definition of the soul should contain no reference to the body or to the soul-body compound. However, there exists a common definition, or more precisely an account resembling a definition (/..Oyov &.vaA.oyoiJvta OQLaµq> ), of the soul as incorporated in the body. 50 But this cannot be the right definition. In his search for a better one, Philoponus recalls that in Posterior Analytics 1.8, Aristotle 49

John Philoponus, In De anima libros commentaria [Hayduck], p. 48 1 3 ff.

so Ibid., p. 48 2 3.



distinguishes three types of definition. These are: (a) the principle of demonstration, (b) its conclusion and (c) a demonstration which differs in the order of terms. 51 To this, Philoponus adds the alternative threefold scheme of De anima 1.1. A definition, so he writes, is classifiable according to (i) form, (ii) matter or (iii) compound. E>uµ6i; is a clear example. Defined according to matter, this word designates the boiling of the blood around the heart. Defined according to the formal components, this word designates a desire for retaliation. Defined according to compound, this word designates a composite of the former two; {}uµ6i; is in this case a boiling of the blood around the heart caused by a desire to retaliate. 52 The two schemata can be brought into agreement: (a) corresponds to (i), (b) to (ii) and (c) to (iii). The definition of the complete soul must logically be based upon such divisions as well. Therefore, if the soul is an immaterial form which accidentally dwells in the body, then definition (a) is applicable. The soul is in this case defined as the form and cause of the body. Ps.-Simplicius also concords with the Aristotelian principle that the definition is the starting point of every demonstration. Nevertheless, there is a minor difference between the two accounts. For Ps.-Simplicius, demonstration is reasoning which progresses from a definition indicating the true nature of the definiendum and arrives at the attributes. There are once again three types of definitions: (i) the conclusion of a demonstration, (ii) the middle term of a syllogism and (iii) the whole syllogism (which differs from the demonstration in the order of the terms ({}foEt) . 53 This means that in a definition, the 51 Aristotle, Posterior Analytics, 75b31-32; see also n.10, 94a11-14. Philoponus explains the difference in the order of terms by saying that the definition must contain the cause that brings about the thing or event (rrQilyµa). 52 Cf. Aristotle's twofold definition of anger (6Qytj) in De anima, 403a30-31. There are two striking differences between Aristotle's and Philoponus' passages. Aristotle has no definition drawn from the compound nor gives precedence to the definition in terms of form to that in terms of matter. Philoponus' definition drawn from the compound suggests that the blood is boiling through (bta) the desire to retaliate. See also John Philoponus, In Analytica posteriora commentaria [Wallis], p. 109 12 ff. 53 Ps.-Simplicius, Simplicii in liltros Aristotelis De anima commentaria [Hayduck], p. 97 8- 26 . A comparable list can be found in Aristotle's Posterior Analytics, n.10, 94a1114. But in Aristotle, one type of definition offers the indemonstrable account of what something is, while in Ps.-Simplicius, this account is identified with the middle term of a syllogism. As for Philoponus, he distinguishes between material definition ( OQtoµoc:; uAtx6c:;), formal definition (oQtoµoc:; dbtx6c:;) and compound definition (OQtoµoc:; ouvitEi:oc:;), see John Philoponus, In Analytica posteriora commentaria [Wallis], p. 3 7 5 2 - 8 . Unlike Ps.-Simplicius, he does not identify the formal definition with the middle term of a syllogism.



effect may precede the cause. When applied to the definition of the soul, this threefold scheme help us distinguish between enmattered and immaterial forms. The first kind of definition refers to the thing caused and informed, which is the thing itself (ngayµa). The second kind of definition refers to form and cause. Finally, the third refers simultaneously to effect and to cause. This last definition concerns the composite according to which man is defined as a rational, mortal, living being. This is the enmattered form. The second definition concerns the soul, since it is the form of the body and responsible for its arrangement. In this way, the soul is defined as an immaterial form. For Ps.-Simplicius, knowledge of the soul can thus be secured in this way. As a cause, the soul is clearer in itself. Instead of giving a general definition of the soul, various kinds of souls must be defined. Unfortunately, the commentator does not investigate beyond the individual human soul, which is understandable, given that he is commenting upon Aristotle's De anima. Let us now turn to the method of psychology. Philoponus accepts that in all kinds of instruction, a fact (i:o on) precedes its reason (i:o c'>L6n) .54 This is so because facts are more obvious to us. To establish this conclusion, Philoponus commences with a traditional list of four "problems": d fon, i:U:on, 6no7:6v i:l fon, cha i:l fon. Since d fon and 6no7:6v i:l fon are included in the other two questions, he feels free to concentrate on d fon and OLa i:l foi:L. According to Philoponus, there are three ways in which one thing can be clearer than another. First, a fact is more clear and more knowable than its reason. An example of this is that it is easier to realize that one has an immortal soul than to reach the same conclusion by argument. Note, however, that Philoponus' distinction does not have to do with perceptible things and their immaterial or hidden causes; after all, we never sense the immortality of our own soul. Secondly, the universal can at times be clearer than the particular. 55 However, Philoponus is not speaking here of a sort of universality that is ontologically prior to the individual, as is shown by the fact that the epithet of universals is "confused" (ouyxExuµ£vov) and that of particulars is "articulated" (0Ll]Q'frgwµ£vov). Knowing that something is a body, for example, precedes knowing what kind of

54 John Philoponus, In De anima libros commentaria [Hayduck], p. 22537-p. 226 1 • On instruction (011\, seep. 3834; p. io6 18- 19; p. 2127-8. 55 Philoponus makes reference here to the Physics (to i 84a21, according to Hayduck's critical apparate to John Philoponus, In De anima libros commentaria [Hayduck], p. 226 18 ). In his chapter to this book, Frans de Haas also argues that xafi6A.ou (or xafi' oA.ou) primarily refers to a thing taken as a whole.



body it is. This shows that Philoponus is not assuming that we know universal concepts before particular instances. Instead, like the text he refers to (Aristotle's Physics I.I), he appears to argue that we first perceive objects in an unqualified manner and only later capture its various features. Babies call every man "father" and every woman "mother" and only later in life learn to distinguish their parents from strangers. Their notions thus evolve from initial vagueness to increasing acuity. The third argument states the following. That which is first from our point of view is clearer than that which is first by nature. That which is more compounded is more knowable to us than that which is more simple. This too is an Aristotelian conception. However, Philoponus diverges from Aristotle in important respects. Given that the soul is not an object of the senses, to establish the soul's factuality requires that it be a sort of Evtef..ExELa. Next, it must be understood how exactly the soul is EVTEAEXELa, what it produces, and in what way it completes the body. 56 One striking difference in Philoponus' account is his belief that different faculties have different Evtef..ExELm. Admittedly, he does not altogether reject the methodological principle employed in Physics I. I. He believes that we must first possess a vague notion of the soul according to the definition given in De anima II. I. Next, we have to describe the parts of the soul one by one and ask if each part has a proper Evtef..ExELa, and if so, how it has it. Finally, from those parts with which we are most familiar and which are the last in the order of nature, we proceed to those parts which are the most valuable by nature. The reason of things is arrived at in this way, because it is by nature, although not according to the order of instruction, that to bLotL precedes to ou. 57 This order is justified by the vague character of the latter. However, it is only by means of this vague notion that we may proceed to the knowledge of things. In this particular case, however, Philoponus does understand the relation between fact and reason in terms of cause and effect. His view is reflective of a basic Neoplatonic conception according to which universals obtained on the basis of the multiplicity of sense perceptions are essentially different from both the universals that are prior to nature, on the one hand, and from the universals or notions (A.oym) that inhere in nature, on the other. The notions of all physical things are contained by Nature, which uses them in order to produce the physical things themselves. 58 56 57 58

bid., P·


Ibid., p. 22637 - p. 227 1. Ibid., p. 2274-5; cf. also John Philoponus, In Physicorum libros commentaria [Vitelli],



The soul is therefore to be studied in the following way: One first grasps the soul in its entirety. One then categorizes its parts or faculties, beginning with its more imperfect parts and terminating with its most perfect part, the intellect, which is first by nature. The capacities within a faculty are ranked in a similar manner: Touch is the lowest form of sense perception, as it is closest to matter, whereas sight is the highest form, since light is involved. 59 However, two difficulties remain. The soul's activities are practically unobservable; in contrast, the activities of the body are obvious, but are indeed instigated by the soul. Thus, bodily activities are indirect evidence (i:exµfiQtov) of the activities of the soul. 60 The faculties of the soul are orientated towards their proper objects: Desire towards the desired object, sense perception towards that which is sensible, etc. Does this then mean that knowledge of the proper object may not precede the examination of the faculties? Generally, Philoponus thought so. Yet he made one important exception-the intellect and how it relates to the intelligible. In this case, the intelligible is more difficult to define simply because it transcends us ( UJtEQ ~µi'i£), whereas the intellect is a faculty which belongs to us. 61 The methodical difference may highlight a division within the soul; the intellect is of a more noble origin than the other parts of the human soul. Aristotle followed this same course, but his explanation, if any, was quite different and certainly less explicit. He could neither integrate the intellect into his notion of nature as the container of the notions and forms of all things. Nor did he ever explicitly state that the intellect precedes nature, even if we might be inclined to think so on the basis of Metaphysics xn.

p. 133°-p. 14 1 • Philoponus argues that 'to llt6't1 is more perfect than 'to 01:1. The two other types of inquiry ('to et /!mi and 'to 'ti i\m1) fall under &1 and 1\161:1 as well, cf. John Philoponus, In De anima libros commentaria [Hayduck], p. 2273. For the diverse instantiations of the universals, see also Simplicius' In Aristotelis Categarias commentarium [Kalbfleisch], p. 8235-p. 83 20 , discussed by A. C. Lloyd, The Anatomy of Neoplatonism, pp. 29, 67; cf. also Steel, "Breathing Thought." 59 John Philoponus, InDe anima libros commentaria [Hayduck], p. 227 26 ff. See also p. 3834ff, where we are told that instruction must start from the parts of the soul, because the knowledge of each faculty is a prerequisite for the knowledge of the entire soul. A similar method of instruction should be applied to philosophy in general, because Philoponus claims that we have to proceed from the incomplete beings (or things in becoming) to the heavenly bodies and the order in them. Only at the end of such inquiries will we reach that which is the cause of their order (ibid., P· 22722-24). 60 Ibid., p. 106 2 4. 61 Ibid., p. 39•5-24.



Ps.-Simplicius runs into the same problems. He is rather perplexed by Aristotle's claim that the study of the soul requires a method proceeding from the more to the less obvious to us. As an intermediate entity, the soul is not a direct object of sense perception. Our commentator proposes two methods which, he thinks, are alluded to by two words at the beginning of De anima. "Study" ('ltewgta) connotes the ascent from the obvious and the transcendence of sense perception to a deeper underlying truth, whereas "knowledge" ( yvwmi:;) refers to rational scientific understanding which proceeds from cause to effect. 62 The first method is called "learning" (µa'ltrimi:;) or "instruction" (ou'laoxaA.ta) and the second "scientific understanding" (£mo-rriµovLxij yvwmi:;). 63 The former is based on sense perception by which the effect is clear and suitable for those who have not completed the inquiry. The latter results from a scientific account which starts from a naturally well-defined cause. 64 Furthermore, scientific understanding proceeds from elementary and proximate causes. 65 This is reflective of the natural order. With this in mind, let us now consider the proper examination of the soul. In the first case (µa'ltrimi:; and OLOaoxaAta), a distinction must be made between essence and attribute. One then starts from the attributes or activities, because the essence is determined from the attributes. But we may not choose just any attribute. 66 Some attributes are proper to the soul; it is from these essential attributes that sense and phantasia must proceed. Ps.-Simplicius uses mathematical numbers to illustrate this. Each number's essence is meaningful in the measure that its quality and quantity can be grasped by the imagination. 67 The method of instruction therefore proceeds from what is clear to us at a perceptual level to what is clear at a natural level. Sense perception is the necessary starting point for the study of the soul, for it is imme-

62 Ps.-Simplicius, Simplicii in lilnm Aristotelis De anima commentaria [Hayduck], p. 8 2 s-3°; the reference is to Aristotle, De anima, 4on7. 63 Ps.-Simplicius, Simplicii in libros Aristotelis De anima commentaria [Hayduck], e.g. p. 93; p. i 4 '6; p. 9627; P· 972g-32. 64 Ibid., p. 96 23-35. Ps.-Simplicius explicitly refers to the beginning of Aristotle's Physics. 65 Ibid., p. 2326-7. For a similar distinction, see also p. 83 6; p. 2103-34. 66 Ibid., p. 93-4. 67 Ibid., p. 15 1 ff. The reference is to the Athenian concept of mathematics according to which imagination plays a crucial role in geometry. Imagination is the store of extended A6ym which have been gathered by discursive reason. Cf. the second Prooemium of Proclus, In primum Euclidis Elementorum commentarii [Friedlein].



diately observable that ensouled beings fundamentally differ from inanimate things. 68 From life we may proceed to the cause of life, the soul. The commentator intends to show that Aristotle's primary aim is to individually define various types of souls rather than to define the soul in a general manner, as this would be too imprecise. This interpretation is primarily based upon a theory of the soul according to which levels of soul-hypostasis belong to different species. Such an interpretation obviously leads to a general dismissal of Aristotle's definition of the soul as that which is the substance as form of the natural body which has life potentially. Ps.Simplicius therefore proposes that a viable explanation should not uniquely depend upon common properties, but must contain specific features as well. This modification has a Neoplatonic character; Aristotle did not have to account for a similar multiplicity of souls. In conclusion, let us make a comparison between the two accounts. The two commentators are dissatisfied with the Aristotelian definition of the soul. For if the soul were a substance as form of a physical body which has life potentially, and ifthe soul were an actualization of a certain physical body, then the independent existence of the soul would be impossible. Philoponus and Ps.-Simplicius are also agreed that such a general definition would be too vague to be adequate. A preferable procedure would begin by classifying and then defining the various soul-strata and the various faculties of the human soul. Philoponus and Ps.-Simplicius also make use of Aristotle's division of definition in Posterior Analytics i.8. However, the two seem to disagree in their application of the threefold division. Philoponus keeps strictly to the division in claiming that one form of definition is the principle of demonstration, whereas Ps.-Simplicius prefers to say that it is the middle term of the syllogism. However, this divergence of opinion is not fundamentally important. Philoponus, for his part, refers to Aristotle in claiming that many definitions falsely resemble the conclusions of syllogisms, although conclusions of course do not contain the cause. Rather, the cause is analogous to the middle term in the syllogism. Being the form and cause of the body, the soul is well expressed by the middle term. As the principle of demonstration, the definition also expresses the form for demonstrations from


Ps.-Simplicius, Simplicii in libros Aristotelis De anima commentaria [Hayduck], p.




causes to effects. However, the form is the cause of the matter. 69 This reasoning proves, then, that there is no contradiction between the claims of the two authors.

3. The Influence of these Ideas in Sixteenth-Century Padua Historically speaking, Philoponus' ideas seem to have fallen into oblivion, with the exception of one important issue. By contrast, the central notion of Ps.-Simplicius' works, which was supported by Proclus, was to emerge later under the guise of scientia medians and was to exert great influence on sixteenth-century Paduan thinkers. His commentary was to become widely read in the late fifteenth and sixteenth centuries. 70 This Renaissance interest in Simplicius is all the more extraordinary as there does not seem to have existed any medieval Latin translation of it. Giovanni Pico della Mirandola is said to have discovered the commentary and to have made it accessible to a Western readership in the late 1480s. In 1486, Pico also summarised the basic principles of the text in the Conclusiones which he probably considered relevant for the contemporary dispute on the immortality of the rational soul. In all probability, the copy he had in his library had been written in Greek. 71 Agostino Nifo used this commentary before it was even available in print. The editio princeps is an Aldine print of 1527 prepared by Francesco Asulano. In 1544,Jacob Schegk edited in Tubingen some portions of the text as a supplement to Aristotle's De anima. The motivation behind this interest had to do with Ps.-Simplicius' conception of internal sense and active intellect. Humanist translations further contributed to the dissemination of these ideas. In 1543, the first translation was published in Venice by Giovanni Fasolo (or Faseolo), who was a disciple of Marc' Anto69 John Philoponus, In De anima libros commentaria [Hayduck], p. 2313--34; see also his In Analytica posteriora commentaria [Wallis], p. 109 16- 2 \ and ibid., p. 1684. 7 For an excellent overview of the influence of Ps.-Simplicius' Commentary on De anima, see Nardi, "II commento di Simplicio a De anima." 71 We cannot rule out, however, that there may also have existed an early, perhaps medieval, translation. That Nicoletta Vernia may have been acquainted with such a translation is suggested by his marginal notes to John of Jandun's Questiones super libros de anima. Nicoletta Vernia knew no Greek. Nor could his marginal notes be explained on the basis of the Conclusiones. See Bossier, Filologisch-historische navorsingen, PP· i5.004-15.015.




nio Genua and professor at Padua. The second translation was made by Evangelista Longo (Asulano) and was published also in Venice, in 1553. However, Asulano claimed to have simply revised Fasolo's version. The third partial translation was made by a Greek humanist, Michael Sophianus, who translated the introductory part of the Prooemium. 72 Note that all these translations were made by persons closely connected to Padua. My aim in this appendix is two-fold. First, I shall draw attention to various issues which illustrate the influence Ps.-Simplicius and Philoponus had upon thinkers in Padua in regards to the status and methods of psychology. Secondly, I shall concentrate on Zabarella's De anima commentary to show that his dissent from the Neoplatonism of his teacher Marc' Antonio Genua goes together with his negative attitude towards the methodological remarks found in Ps.-Simplicius' De anima commentary. There are four points I should like to stress here. First, the predominant view concerning psychology actually facilitated the reception of Ps.-Simplicius' ideas. Agostino Nifo, for example, recognized psychology as a scientia media between metaphysics and physics. 73 This view remained prevalent among those Paduans who combined Averroism with a strain of Neoplatonism. Only Zabarella eventually broke with this view when trying to liberate methodology from ontology. 74 Textual parallels with Ps.-Simplicius found in the writings of a number of Paduan thinkers document the influence of the Greek commentator, not only with respect to the theory of active intellect, but also regarding the status of psychology. A second point concerns the criteria for ordering the sciences hierarchically. Aristotle had mentioned the dignity of the subjectmatter and exactness of the method as his two criteria. In the wake of Averroes, many Paduan thinkers thought that these two criteria were equally important. 75 We recall, however, that Philoponus had emphasized the dignity of subject-matter; in this, he was followed by 72 Preserved in MS Milano, Biblioteca Ambrosiana, D 465 inf Jase. i 2. See Hayduck's introduction in Ps.-Simplicius, Simplicii in libros Aristotelis De anima commentaria [Hayduck], p. vii, and Suppl. rv on p. xiv; cf. also Bossier, Filologisch-historische navorsingen, i5.015. 73 Nifo, Expositio in libros Aristotelis De anima, "Prooemium in collectanea," col. 3. The reference is from Kessler, "Von der Psychologie zur Methodenlehre," p. 55i. Nifo's arguments are reminiscent of those used by Ps.-Simplicius in the introduction to his commentary. 74 Zabarella, Commentarii in De anima, col. i 1E-D. 75 For an overview, see Olivieri, "La scientificita."



Agostino Nifo. 76 By contrast, Ps.-Simplicius had intertwined the two criteria by connecting method and ontology. The examples he had given to illustrate this interconnection were repeatedly used by both Averroes and the Paduans, for instance his example of geometry being more exact than astronomy; and of astronomy being more precious than the geometry of optical rays. 77 Stars and other celestial phenomena-so Ps.-Simplicius' assumption-cannot be more valuable than circles and triangles, because the latter derive directly from intelligible entities. Averroes later appropriated this example, but without accepting its Neoplatonic background. 78 Zabarella, in turn, wondered whether the two criteria were equally important. In his discussion about how a science can be more exact than another science, he recurred to the threefold distinction found in Posterior Analytics 1.27. But in his De anima commentary, he only mentions two criteria: the necessity of the subject-matter and the knowledge of causes. Philoponus had mentioned the same two criteria, but without asking himself whether they might ever contradict one another. Zabarella, however, shows that it is indeed possible for them to do so. The subject-matter of astrology is more valuable than that of geometry. In this respect, astrology has primacy over geometry. But in terms of our knowledge of causes, astrology proves less valuable than geometry. The third point concerns Aristotle's statement that the study of the soul greatly contributes to all truth, particularly to the truth of

76 Nifo, Expositio in libros Aristotelis De anima, cols. 3 and 12: "Et cum hoc ita sit, patet secundum expositionem Graecorum, quad Aristoteles non anteponit hanc scientiam aliis propter firm um genus demonstrandi et nobilitatem subiecti." Quoted in Kessler, "Method in the Aristotelian Tradition," p. 12 1. Nifo must have relied on Philoponus here, because Ps.-Simplicius has a different view and Sophonias' work is a paraphrase of Philoponus' (one must also doubt if it was accessible to Nifo). As for Philoponus' De anima commentary, the editio princeps was published in 1535 in Venice (see John Philoponus, Commentaria in libros De anima), the first humanist translation appeared in 1544, also in Venice (see John Philoponus, In tres libros De anima breves annotationes), with many reprints thereafter. For a checklist of the editions and humanist translations of Philoponus' works, see Schmitt, "Philoponus' Commentary on Aristotle's Physics," pp. 228-230. 77 Ps.-Simplicius, Simplicii in libros Aristotelis De anima commentaria [Hayduck], p.


78 Averroes, Commentarium magnum in De anima libros [Crawford], p. 3. The example is also taken over by Federico Pendasio in his Lectiones in libros De anima, MS Padova, Biblioteca Universitaria, 1264, p. 60; see Olivieri, Certezza e gerarchia del sapere, p. 187.



nature. 79 Ps.-Simplicius had explained, as we recall, that psychology contributes to the physical sciences, because the soul is the principle ofliving things and contains A.oym derived from the intellect, thanks to which the soul is capable of recognizing physical objects. These A.oym are akin to forms in nature. 80 The obvious conclusion had to be that the study of the soul is the basis of the study of nature. Agostino Nifo drew the very same conclusion when he wrote that the soul receives the ideas of all things as a sort of form. Thus, in thinking of these ideas, the soul thinks of all things. 81 In this way, the study of the soul becomes an inevitable premise for the study of nature. As far as the question of method is concerned, Ps.-Simplicius had clearly distinguished fabaoxal..La from yvwov::; and had thereby anticipated the distinction between the ordo doctrinae and the order inherent in natural things. However, he had not gone as far as Zabarella, who was to assert that the ordo doctrinae cannot be based on the natural order. 82 In Zabarella's eyes, instruction is only suitable for those who have not completed their inquiry; he also maintained that scientific explanation must follow nature. 83 Let us now briefly turn to Zabarella's De anima commentary and see where he relies on the doctrines of Philoponus and Ps.-Simplicius. Given how critical Zabarella was of the Neoplatonic tendencies of his teacher, Marc' Antonio Genua, it is not surprising to find that he also rejected the main thrust of Ps.-Simplicius' interpretation. This rejection is sometimes merely implied by his words, but in other cases becomes very explicit and ranges from the explanation of certain terms to doctrines of a more general kind. Nevertheless, he also uses arguments directly borrowed from Ps.-Simplicius. Let me mention one example of a terminological disagreement. At the very beginning of De anima, Aristotle says that E'Lbrim::; is a fine and pre79 Aristotle, De anima, 402a4-5. Ps.-Simplicius, Simplicii in libros Anstotelis De anima commentana [Hayduck], p. 87- 1 7. The A.Oyo~-theory is characteristic for Athenian Neoplatonism (see, e.g., Priscianus Lydus, Metaphrasis in Theophrastum [Bywater], p. 1 1 -p. 59; Ps.-Simplicius, Simplicii in libros Anstotelis De anima commentana [Hayduck], p. 118 2 9-p. 119 2 9) and may have originated in Iamblichus. 81 Nifo, Expositio in libros Anstotelis De anima, col. 25: "qui ergo earn sic idaeis (sic) formatam intelligeret, veritates omnium rerum intelligeret." Quoted in Kessler, "Method in the Aristotelian Tradition," n. 75. It cannot be ruled out that Nifo took this concept from Averroes; however, Averroes used a different methodology in the relevant section of his commentary on De anima. 82 Zabarella, Opera logi,ca, cols. 140-144, 183-185. 83 Ps.-Simplicius, Simplicii in libros Anstotelis De anima commentana [Hayduck], p. 80




cious thing. But what does Eto11mc:; mean? Does it specifically refer to scientific knowledge or to knowledge in general? Zabarella rejects Ps.-Simplicius' assumption that the term refers to perfect knowledge and sides with Philoponus in stating that ELO'l']mc:; can refer to any kind of knowledge ( notitia). 84 He maintains that Aristotle had wished to classify psychology within the context of knowledge in general. This implies that Zabarella's aim is not to define the status of psychology vis-a-vis the demonstrative sciences, but rather to place it within the body of science as a whole. As for doctrinal differences, Zabarella follows once more Philoponus in his claim that the excellence of study depends upon the dignity of its object. Exactitude of method in not in itself a guarantee of precedence within the hierarchy of sciences. A discipline relying on exact methods is only more noble secundum quid. Its absolute worth is in fact defined by the value of the objects it investigates. 85 However, Zabarella does not accept all of Philoponus' explanations. In fact, he does not even accept the conclusion of his famous predecessor. According to Zabarella, Philoponus' assumption that the study of the soul is most reliable (certissima) in a secondary sense is wrong. Philoponus had argued that while psychology was surpassed by mathematics in terms of demonstrative force, it was reliable in terms of the subject-matter, the soul. 85 One of Zabarella's arguments against this claim is that the baser parts of the soul are linked to matter, which makes it impossible to treat the human soul as a perfect object for any science. Zabarella' s most important criticism of Ps.-Sim plicius' interpretation concerns the concept of scientia media. We recall that the Greek commentator had advocated for psychology a middle position between the physical sciences and metaphysics. Zabarella critically discusses the foundations of this interpretation. 87 Observing that Aristotle had regarded his De anima as one of the libri naturales and hence 84 Zabarella, Commentarii in De anima, cols. 3}'-4B; see especially: "Prim um quidem, quia non est verum id, quod Simplicius